The purpose of this research study was to explore the process of learning and development of problem solving skills in radiologic technologists. The researcher sought to understand the nature of difficult problems encountered in clinical practice, to identify specific learning practices leading to the development of professional expertise, and to uncover workplace conditions that support learning and enable problem solving. A case study approach was employed to explore and describe the workplace learning experiences of a relatively small sample of radiologic technologists. Qualitative and quantitative data were collected from 22 technologists employed at six hospital worksites. Qualitative data consisted of in-depth semi-structured interviews; quantitative data consisted of demographic questionnaire responses, Reasoning about Current Issues [RCI] assessment scores, and hypothetical problem scores derived from the interview data. Descriptive and analytical tests were performed on quantitative data using SPSS 17.0. The researcher sought to discover relationships among the following variables: age, experience, highest level of education completed, RCI scores, and hypothetical problem scores. One to two managers or supervisors from each worksite were also briefly interviewed to assist the researcher in understanding the workplace culture at each research site. Results of the study suggest that the most difficult problems technologists face in clinical practice are often complex in nature, with technical and non-technical aspects, well-structured and ill-structured aspects. Technologists develop advanced problem solving skills through experience with real-life dilemmas encountered in the workplace, primarily through informal means, using a combination of deliberate and unintentional learning practices. Mentoring and collaboration played key roles in subjects' learning and problem solving. Experience alone did not result in problem solving expertise for the sample. Differences were identified in the ways "expert" problem solvers approached learning and solved problems as compared to "challenged" problem solvers. Certain workplace conditions supported subjects' learning and enabled problem solving. Specific learning practices enhance the development of professional expertise including deliberately working through difficult problems, deliberate reflection on work alone and with peers, and adjusting practice in response to feedback. Learning communities within medical imaging departments support technologists' development of problem solving skills and could potentially result in improved patient outcomes. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.